Recently, concern about ecology has increased, ocean disposal of processing chemicals used for silver halide photographic materials is prohibited and there is increasing pressure to release the amount of processing chemicals used in medical care.
To compensate for consumption of developer components during development, processing chemicals are replenished at the rate to keep constant the amounts of the processing chemicals supplied to the silver halide photographic material. To reduce the amount of processing chemicals being used, replenishment is desired to be done at a low replenishing rate. However, when processed at a low replenishing rate, the residence time of the developer solution in a developing tank increases, producing problems that the developer is much more subjected to oxidation and hence developing activity thereof is lowered.
As an automatic processor systems used for processing silver halide black-and-white photographic materials have been employed plural systems having a variety of functions and specifications corresponding to various uses and facilities, including small and large processors, standard processes and rapid processes, low replenishing processes and ultra-low replenishing processes.
Specifically, small-sized processors are popular among small-scaled facilities mainly for medical practitioners because of their space-saving, light weight and simplicity.
The number of clients per day in a medical practitioner facility is limited, in which films including X-ray photographs, MRI images outputted by a laser imager and ultrasonic images photographed by a G-camera are processed using an automatic processor, even though the processing amount thereof is small. In cases when the processing amount is relatively small, replacement per unit time of the developer solution used in the processor is lowered to prolong the residence time of the developer solution, increasing influences of oxidation exhaustion and resulting in reduced developing activity. Accordingly, an important factor is how to maintain running process stable over a long period of time in the such small-sized processor systems.
As a feature of the small processor, the space for processing tanks is limited so that the processing path length is short and the transport rack has a simple structure (having fewer rollers), making it difficult to achieve the levels of developability or fixability of medium- or large-sized processors. In light of the characteristics of the small processors with respect to the structure and the usage thereof, improvements in process stability and development uniformity are strongly sought.
To overcome these problems were disclosed various means, such as the open top area of the developing tank being extremely reduced, the pH of the developer solution being lowered to lessen development activity to enhance development stability, an antioxidant is added, or the flow velocity of the developer solution being more precisely controlled. However, there were problems that the developer solution contained dihydroxybenzene developing agents and even in cases of the developer containing reductons, its development stability was insufficient. Further, there were marked problems in fluctuations of temperature and variation with respect to density or silver amount of the photographic material being processed.